CN1019961C - Flow-field stern shape suitable for the propulsion of ship with large radius-depth ratio - Google Patents

Abstract

The present invention provides a flow field stern which is different from a common stern in that a stern shape, a screw propeller and a ship rudder are integrally taken into account, so that the shape of the stern can generate a suitable flow field for the screw propeller to work, the screw propeller can still work efficiently after the screw propeller disk area is enlarged, and the work efficiency of the screw propeller is raised by increasing incoming flow. The flow field stern is especially suitable for a ship with a shallow draft. The present invention can be used by cooperating with a ducted screw propeller or a none-ducted screw propeller to improve a navigation capability without increasing the main engine power of the ship.

Description

Flow-field stern shape suitable for the propulsion of ship with large radius-depth ratio

The present invention relates to boats and ships flow field stern type, be applicable to coastal marine site, the power vessels of the Changjiang river, lake and each inland waters and various Fishery Vessel, be particularly suitable for the drinking water of the shallow draft in shallow water territory and hyperline in, heavy load, the boats and ships that single, double screw propeller advances.

Existing shallow water territory is to go to design shaping from the angle that reduces resistance with the stern type of various shallow draft boats and ships isolatedly, screw propeller then isolatedly is analyzed the selection parameter from improving its spacious water efficient, the two considers the influence of the two respectively after the individual processing again, predict its key property, think that promptly screw propeller works independently in ship stern flow field, ship stern flow field is the simple superposition in single ship and single-blade flow field.Therefore, existing ship stern type isolatedly consider and ignored influence to advancing fully from the angle that reduces ship resistance, and presses the spacious aqueous condition of screw propeller, and the parameter of decision is ignored the existence of hull shape again.This just causes propulsion coefficient not high, manoeuvre of ship ability variation, and particularly the light-draft boats and ships in shallow water territory are particularly serious.And the basin of China's natural river depth of water is limited, and the coastal water major part also is a shallow waters, therefore improves the propulsion capability and the operating function of shallow draft power vessels, breaks through conventional method of designing and has special significant meaning.Once adopt flat type or stream line pattern abroad, domestic adopted stream line patterns more, but all can not propose the breakthrough of essence.Therefore, the variety of problems such as low efficiency that exist in the present invention is directed to the propelling of shallow water territory shallow draft and ultra-shallow draft power vessels and handling, proposition designs the requirement of ship stern type and propelling, manipulation as a whole with raising speed and propulsive force, rather than reaches this purpose with the capacity that increases main frame.And the shape that makes the ship stern can cause and help screw propeller and give full play to efficient, help improving the manoeuvre of ship performance, the propelling and the road-holding property of these boats and ships of favourable flow field that the ship stern causes make when propeller blade partly surfaces under worst situation, owing to also can be greatly improved.This is because the flow field that the ship stern that adopts the present invention to propose forms can form stronger contraction a fluid stream in oar dish the place ahead, the screw propeller that card has been increased also can suck current under than the situation of light load, get rid of retention (more than the water surface) air in the stern tunnel, the current that need when fully guaranteeing screw propeller work, make ship stern type adapt to the needs that screw propeller advances and handles thereby reach, the ship stern type that the present invention proposes may increase resistance, but the flow field that is complementary with screw propeller that it causes will be improved operating function and be increased substantially propulsion coefficient, and its gross earnings is much larger than the increase of resistance.

The boats and ships stern type that the present invention proposes with ship stern type with propelling, handle and take design into consideration and be shaped, and the speed that makes the formed flow field of design-calculated ship stern type and distribution of pressure make it to satisfy to increase propeller disc area, increase wake flow sectional area, to cause the requirement of approach such as even wake with the marine propeller momentum theory of raising propulsion coefficient.So that screw propeller still can turn round when surfacing efficiently.Ship stern shaped design becomes to cause a kind of a fluid stream in screw propeller the place ahead, works the work that shrinks current in order to increasing speed of incoming flow before the oar, and a fluid stream that caused of stern type makes its rotation help utilization to the circumferential induction velocity of screw propeller as far as possible.Continue to form the continuous a fluid stream that goes at rear propeller, angle of run should be as far as possible little, to closed stern end angle of run below 14 °, can be used for open type stern end for reducing angle of run the present invention, be that the stern end does not seal, and establish the movable cover plate of a pivotally attached stream line pattern, adopt rubber sheet gasket in conjunction with the stern end at it at the stern end, reduce angle of run to prolong after run, will prevent especially that simultaneously air from sucking.

The shape of the boats and ships stern type that the present invention proposes is to make formed a fluid stream produce the bigger and even wake of trying one's best.

The boats and ships stern type that the present invention proposes is not that list is that purpose is determined its shape from reducing resistance, but a kind of stern type and screw propeller, rudder for ship are taken into consideration so that in the speed in the ship stern flow field that forms and the propelling unit momentum theory that distribution of pressure satisfies ship in the propulsion coefficient expression formula to increase rotor disk area A, increase incoming flow V and improve the stern type that the theory of propulsion coefficient η requires.

Described propulsion coefficient expression formula is:

${\eta }_{\mathrm{A\; i}}=\frac{2}{\mathrm{1\; +}\sqrt{\mathrm{1\; +\; \sigma \; ＇\; T}}}$

Wherein

η _Ai-desirable propulsion coefficient;

T _i-thrust;

ρ-water tightness;

A _o-propeller disc area;

V _A-oar the place ahead incoming flow.

In ship design in the past, can not be implemented in when increasing rotor disk area A, incoming flow V is increased.And after the present invention introduced the design of boats and ships stern type to the screw propeller momentum principle, the large radius-depth that obtains was than advancing flow field stern type then to produce such result.

The boats and ships stern type base model that the present invention proposes is such: the stern type vertically contour shape of the bench section at each position is approximate arch, has lonely shape top, garden in the screw propeller region, along with front and back are gradually mild away from garden, the top orphan of the stern type cross section shape at screw propeller place, dome height also descends thereupon, the both sides of each cross-sectional profile shape are connected with straight shipboard face transition glossily, the arch span of each cross-sectional profile shape is different, square broad in face of the oar, asymptotic oar card and reducing gradually, rearward increase gradually again from the oar card, stern type elevation profile contour shape is can play half mozzle effect and can form the tunnel-like of shrinking a fluid stream of rotation to the ship stern.

That is to say, the present invention proposes the method for designing of the new stern type of a kind of boats and ships, it is characterized in that, this method of designing is that the design of stern type combines with propeller, rudder fluid behaviour, by propeller place incoming flow with go flow field control, form the contraction of ship stern streamline and prewhirl, to strengthen propeller the place ahead speed of incoming flow, increase the propeller disc area simultaneously, particularly, increasing the propeller disc area makes propeller exceed drauht line above (D/T≤1.4, D-propeller diameter, T-drauht) still to keep high propulsion coefficient.

The present invention also proposes the new stern type of a kind of boats and ships, it is characterized in that the base model of this stern type is: a little the length L of hoisting that is arched upward by ship stern end to hull bottom line tunnel-like ₁Scope be boats and ships waterline length L _WL30%-60% between, play lift angle θ ₁Be 13 °-25 °, maximum sagitta place, its tunnel (being the propeller present position) is apart from ship stern end length L ₂For one to two propeller diameter, hold slow transition from maximum sagitta level with both hands to stern, angle of run θ ₂≤ 14 °, at ship stern end place, the heavy dark amount △ d ' of enclosed stern end below the drauht line 〉=0.1 meter, surmount △ d 〉=0.05 of open type stern end more than the drauht line meter.

Boats and ships stern cross section shape shrinks to form evenly in advance in a fluid stream for making current in propeller the place ahead, can make the evenly asymmetric arch form of diffusion of a fluid stream appropriateness again at the propeller rear, at the propeller place, the height maximum in ship stern horizontal stroke, elevation profile, vertex is the drauht line with down to more than the drauht line, choosing height value can control this position fluid storage and flow to discharge and make propeller diameter and drauht than D/T≤1.4, shipboard position, ship stern bench section sinks so that propeller the place ahead aspirated air not, its sinking value △ ds 〉=0.2 meter.

3. according to the described boats and ships stern of claim 2 type, it is characterized in that this boats and ships stern type can be open type tunnel-like stern type,, install special tortoise lid type cover plate additional at the stern end for keeping the just ability of falling the boat.

Fig. 1 is stern type elevation profile, the twin screw flow field contour shape scheme drawing that the present invention proposes;

Fig. 2 is the flow field stern type cross-sectional profile shape scheme drawing that each lengthwise position of relative Fig. 1 is done;

Fig. 3 is stern type elevation profile, the single screw flow field contour shape scheme drawing that the present invention proposes;

Fig. 4 is the flow field stern type cross-sectional profile shape scheme drawing that each lengthwise position of relative Fig. 3 is done;

Fig. 5 is the elevation profile contour shape scheme drawing of existing triangle line style stern type;

Fig. 6 is the cross-sectional profile shape scheme drawing of the existing triangle line style stern type that each lengthwise position is done among relative Fig. 5;

Fig. 7 is the elevation profile contour shape scheme drawing of existing knuckle line stern type;

Fig. 8 is the cross-sectional profile shape scheme drawing of the existing knuckle line stern type that each lengthwise position is done among relative Fig. 7.

A is an open type stern end among the figure, and B is an enclosed stern end, and C is a screw propeller, and E is the stern end points, h _TBe the tunnel top line height, β is for dividing water heel angle.In conjunction with the accompanying drawings 1,2 and 3,4 and Fig. 5,6 and 7,8, the flow field stern type that proposes of the present invention and the difference of existing stern type as can be seen.

Vertically play lift angle θ behind the midship of the boats and ships stern type that the present invention proposes ₁Be about 20 °, this angle is the smaller the better.Vertically play the inclination transition gently of lift angle place and shipboard behind the midship, avoid interlayer to separate and produce eddy current to stern.These needs of being not only the flow field also are to guarantee fully to supply with the needs that screw propeller is inhaled stream.

Its stern end of boats and ships stern type that the present invention proposes for can sink to below the drauht line apart from △ d '=0.1 meter or maybe can exceed below 0.1 meter more than the drauht line apart from △ d=0.05 rice or two kinds of forms more than 0.05 meter, the above coastal water of the heavy dark edge △ ds=0.2 rice of shipboard boats and ships then should could guarantee not aspirated air like this more than 0.4 meter.

The boats and ships stern type that the present invention proposes is for twin-propeller, and its minute water heel β is tilted should be about 15 ° by the bottom upward.

The large radius-depth that the present invention proposes is expressed as follows than the basic specification scope and the symbol connotation of flow field stern type: (as Fig. 1,2 and Fig. 3,4)

Large radius-depth is than length of tunnel L ₁;

Boats and ships waterline length L _WL;

The propeller center line to the stern end distance from L ₂; L ₂';

The tunnel plays lift angle θ ₁;

To stern angle of run θ ₂;

The stern end sinks dark △ d ';

The stern end exceeds △ d;

The stern shipboard sinks dark △ ds;

Tunnel top line height h _T;

Drauht d;

Diameter of propeller D.

The scope of above-mentioned each parameter is as follows:

L ₁/L _WL＝0.3-0.6;

D/d＝1.0-1.4;

L ₂'=1D-2D(is for enclosed stern end);

L ₂=1D-1.5D(is for open type stern end);

θ ₁＝13°-25°;

θ ₂≤ 14 °; △ ds 〉=0.2 meter;

△ d ' should be 0.1 meter to enclosed stern end for sinking to the drauht amount, or below 0.1 meter;

△ d opposite opened stern end should be more than 0.05 meter or 0.05 meter for exceeding the drauht amount;

The flow field stern type that the present invention proposes can be stern end points surface the open type tunnel-like of height △ d or the enclosed tunnel-like that the stern end points immerses underwater degree of depth △ d ', and boats and ships stern when navigating of open type tunnel-like stern type is equipped with the stern cover plate.

The flow field concrete parameter of stern type that the present invention that No. 319 push boats of the E Hang of hubei province shipping company adopt proposes is as follows:

L _WL=23 meters, beam B=8.0 rice, D=1.9 rice

D=2.0 rice, power Ne=2 * 136 kilowatt

Ship stern parameter:

L ₁/L _WL＝0.596，θ ₁＝17.5°

θ ₂=11 °, L ₂'=3.2 meters

△ d '=0.1 meter, △ ds=0.20 rice

h _T=2.30 meters

The positive bollard pull of real ship is 7.53 tons, and the bollard pull that falls is 6.43 tons, push away 11.26 kilometers of speed of a ship or plane degree/time, push away 2229 tons of cargo capacitys.

Hunan Province shipping office No. 4208 push boats of Hunan boat are shrouded propeller, and the flow field concrete parameter of stern type that adopts the present invention to propose is as follows:

L _WL=23 meters, beam B=7.0 rice, D=1.3-1.5 rice

D=1.61 rice, power Ne=2 * 100 kilowatt

Ship stern parameter:

L ₁/L _WL＝0.457，θ ₁＝17.3°

θ ₂=6 °, L ₂=2.35 meters

△ d=0.2 rice-0(is an open type ship stern), △ ds=0.24 rice

h _T=1.74 meters

5.9 tons of real tensile force for boat column, push away 10.5 kilometers of speed of a ship or plane degree/time, push away 1500 tons of cargo capacitys.

Sichuan Province shipping office No. 12 ships of river bullock are non-mozzle screw propeller, and the flow field concrete parameter of stern type that adopts the present invention to propose is as follows:

L _WL=26 meters, beam B=5.2 rice, D=1.25 rice

D=1.5 rice, power Ne=2 * 110 kilowatt

Ship stern parameter:

L ₁/L _WL＝0.385，θ ₁＝14.7°

θ ₂=13 °, L ₂'=2.15 meters

△ d '=0.1 meter, △ ds=0.2 rice

h _T=1.57 meters

4.3 tons of the positive bollard pulls of real ship, 15 kilometers of Design Speeds/time.

12.66 kilometers of towage speed/time, 3.1 tons of towing tensions, 20.7 kilometers of sailing speeds/time.

The flow field stern type that adopts the present invention to propose, when being used as push train when using the combination of mozzle screw propeller and all kinds of rudder, with relatively its kiloton kilometer traffic cost reduction more than 40% of existing common boat team, kiloton kilometer consumption of fuel reduces more than 40%, with regard to the unit push boat, navigation thrust can improve 10-25%.When using the combination of non-mozzle screw propeller and all kinds of rudder, compare kiloton kilometer traffic cost reduction 8-15% with adopting common ship stern, kiloton kilometer consumption of fuel reduces 10-17%.Single ship thrust improved 7-17% when rudder was capable.

The flow field ship stern that the present invention proposes compares with the boats and ships of weight, middle load, the restricted common power driven vessel stern of diameter of propeller, gives meter kiloton kilometer cost and can reduce by 8%, and kiloton kilometer consumption of fuel can reduce about 10%, and navigation thrust can improve 5-10%.

Claims (3)

1, a kind of ship with large radius-depth is than the method for designing that advances flow field stern type, it is characterized in that, this method of designing is that the design of stern type combines with propeller, rudder fluid behaviour, by screw propeller place incoming flow with go flow field control, form the contraction of ship stern streamline and prewhirl, to strengthen screw propeller the place ahead speed of incoming flow, increase the propeller disc area simultaneously, particularly, increasing the propeller disc area makes propeller exceed above (D/T≤1.4 of drauht line, D-propeller diameter, T-drauht) still keeps high propulsion coefficient.

2, a kind of ship with large radius-depth is characterized in that than advancing flow field stern type the base model of this stern type is: a little the length L of hoisting that is arched upward by ship stern end to hull bottom line tunnel-like ₁Scope be boats and ships waterline length L _WL30%-60% between, play lift angle θ ₁Be 13 °-25 °, maximum sagitta place, its tunnel (being the propeller present position) is apart from ship stern end length L ₂For one to two propeller diameter, hold slow transition from maximum sagitta level with both hands to stern, angle of run θ ₂≤ 14 °, at ship stern end place, the heavy dark amount △ d ' of enclosed stern end below the drauht line 〉=0.1 meter, surmount △ d 〉=0.05 of open type stern end more than the drauht line meter.

Boats and ships stern cross section shape shrinks to form evenly in advance in a fluid stream for making current in propeller the place ahead, can make the evenly asymmetric arch form of diffusion of a fluid stream appropriateness at rear propeller again, at the propeller place, the height maximum in ship stern horizontal stroke, elevation profile, vertex is the drauht line with down to more than the drauht line, choosing height value can control this position fluid storage and flow to discharge and make propeller diameter and drauht than D/T≤1.4, shipboard position, ship stern bench section sinks so that propeller the place ahead aspirated air not, its sinking value △ ds 〉=0.2 meter.

3, a kind of ship with large radius-depth according to claim 2 is characterized in that than advancing flow field stern type this boats and ships stern type can be open type tunnel-like stern type, for keeping the just ability of falling the boat, installs special tortoise lid type cover plate additional at the stern end.

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